LIGHT
LIGHT
T
he world is largely known through
the senses. The sense of sight
is one of the most important
senses. Through it we see mountains,
rivers, trees, plants, chairs, people and
so many other things around us. We also
see clouds, rainbows and birds flying
in the sky. At night we see the moon
and the stars. You are able to see the
words and sentences printed on this
page. How is seeing made possible?
13.1 What makes Things
Visible
Have you ever thought how we see
various objects? You may say that eyes
see the objects. But, can you see an
object in the dark? It means that eyes
alone cannot see any object. It is only
when light from an object enters our
eyes that we see the object. The light
may have been emitted by the object, or
may have been reflected by it.
You learnt in Class VII that a polished
or a shiny surface can act as a mirr
or. A
mirror changes the direction of light
that falls on it. Can you tell in which
dir
ection the light falling on a surface
will be reflected? Let us find out.
13.2 Laws of Reflection
Activity 13.1
Fix a white sheet of paper on a
drawing board or a table. Take a
comb and close all its openings
except one in the middle. You can
use a strip of black paper for
this purpose. Hold the comb
perpendicular to the sheet of paper.
Throw light from a torch through
the opening of the comb from one
side (Fig. 13.1). With slight
adjustment of the torch and the
comb you will see a ray of light along
the paper on the other side of the
comb. Keep the comb and the torch
steady. Place a strip of plane mirror
in the path of the light ray
(Fig. 13.1). What do you observe?
After striking the mirror, the ray of
light is reflected in another direction.
The light ray, which strikes any surface,
is called the incident ray. The ray that
comes back from the surface after
reflection is known as the reflected ray.
Fig. 13.1 : Arrangement for showing reflection
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A ray of light is an idealisation. In
reality, we have a narrow beam of
light which is made up of several
rays. For simplicity, we use the term
ray for a narrow beam of light.
Draw lines showing the position of
the plane mirror, the incident ray and
the reflected ray on the paper with the
help of your friends. Remove the mirror
and the comb. Draw a line making an
angle of 90º to the line representing the
mirror at the point where the incident
ray strikes the mirror. This line is known
as the nor
mal
to the reflecting surface
at that point (Fig. 13.2). The angle
Table 13.1 : Angles of Incidence
and Reflection
S. Angle of
Angle of
No. Incidence (
∠
∠
∠
∠
∠i) Reflection (
∠
∠
∠∠
∠r)
1.
2.
3.
4.
5.
Do you see any relation between the
angle of incidence and the angle of
reflection. Are they approximately equal?
If the experiment is carried out carefully,
it is seen that the angle of incidence is
always equal to the angle of reflection.
This is one of the
laws of reflection
.
Let us perform another activity on
reflection.
What would happen if I
threw the light on the
mirror along the normal.
Activity 13.2
Perform Activity 13.1 again. This
time use a sheet of stiff paper or a
chart paper. Let the sheet project a
little beyond the edge of the Table
(Fig. 13.4). Cut the projecting
portion of the sheet in the middle.
Look at the reflected ray. Make sure
that the reflected ray extends to the
projected portion of the paper. Bend
that part of the projected portion on
which the reflected ray falls. Can
you still see the reflected ray? Bring
the paper back to the original
Fig. 13.2 : Drawing the normal
Fig. 13.3 : Angle of incidence and angle of
reflection
Reflected
ray
Normal
Incident
ray
between the normal and incident ray is
called the angle of incidence (
∠∠
∠∠
∠i). The
angle between the normal and the
reflected ray is known as the
angle of
reflection (
∠∠
∠∠
∠r) (Fig. 13.3). Measure the
angle of incidence and the angle of
reflection. Repeat the activity several
times by changing the angle of
incidence. Enter the data in Table 13.1.
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position. Can you see the reflected
ray again? What do you infer?
with the Sun as the source of light
instead of a torch. You, too, can use the
Sun as the source of light.
These activities can also be performed
by making use of the Ray Streak
Apparatus (available in the kit
prepar
ed by NCERT).
Boojho remembered that in Class VII,
he had studied some features of the
image of an object formed by a plane
mirror. Paheli asked him to recall
those features:
(i) Was the image erect or upside
down?
(ii) Was it of the same size as the
object?
(iii) Did the image appear at the same
distance behind the mirror as the
object was in front of it?
(iv) Could it be obtained on a screen?
Let us understand a little more about
the formation of an image by a plane
mirror in the following way:
Activity 13.3
A source of light O is placed in front
of a plane mirror PQ. Two rays OA
and OC are incident on it (Fig. 13.5).
Can you find out the direction of
the reflected rays?
Draw normals to the surface of
the mirror PQ, at the points A and
C. Then draw the reflected rays at
the points A and C. How would you
draw these rays? Call the reflected
rays AB and CD, respectively.
Extend them further. Do they meet?
Extend them backwards. Do they
meet now? If they meet, mark this
point as I. For a viewer’s eye at E
(Fig. 13 .5), do the reflected rays
(b)
Fig. 13.4 (a), (b) : Incident ray, reflected ray
and the normal at the point
of incidence lie in the same
plane
When the whole sheet of paper is
spread on the table, it represents one
plane. The incident ray, the normal at
the point of incidence and the reflected
ray are all in this plane. When you bend
the paper you create a plane different
from the plane in which the incident
ray and the normal lie. Then you do not
see the reflected ray. What does it
indicate? It indicates that the incident
ray, the normal at the point of
incidence and the reflected ray all lie
in the same plane. This is another law
of reflection.
Paheli and Boojho performed the
above activities outside the classroom
(a)
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appear to come from the point I.
Since the reflected rays do not
actually meet at I, but only appear
to do so, we say that a virtual image
of the point O is formed at I. As you
have learnt already in Class VII,
such an image cannot be obtained
on a screen.
You may recall that in an image
formed by a mirror the left of the object
appears on the right and the right
appears on the left. This is known as
lateral inversion.
13.3 Regular and Diffused
Reflection
Activity 13.4
Imagine that parallel rays are
incident on an irregular surface as
shown in Fig. 13.6. Remember that
the laws of reflection are valid at
each point of the surface. Use these
laws to construct reflected rays at
various points. Are they parallel to
one another? You will find that
these rays are reflected in different
directions. (Fig. 13.7)
When all the parallel rays reflected
from a rough or irregular surface are
not parallel, the reflection is known as
diffused or irregular reflection.
Remember that the diffused reflection
is not due to the failure of the laws of
reflection. It is caused by the
irregularities in the reflecting surface,
like that of a cardboard.
On the other hand, reflection from
a smooth surface like that of a
mirror is called regular reflection
(Fig. 13.8). Images are formed by
regular reflection.
Fig. 13.5 : Image formation in a plane mirror
Fig. 13.6 : Parallel rays incident on
an irregular surface
Fig. 13.7 : Rays reflected from irregular
surface
Fig. 13.8 : Regular reflection
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Let us find out.
13.4 Reflected Light Can be
Reflected Again
Recall the last time you visited a hair
dresser. She/he makes you sit in front of
a mirror. After your hair cut is complete,
she/he holds a mirror behind you to show
you how the hair has been cut
(Fig. 13.9).
Do you know how you could
see the hair at the back of your head?
Paheli recalls having constructed a
periscope as an Extended Activity in
Class VI. The periscope makes use of
two plane mirrors. Can you explain
how reflection from the two mirrors
enables you to see objects which are
not visible directly? Periscopes are
used in submarines, tanks and also
by soldiers in bunkers to see things
outside.
13.5 Multiple Images
You are aware that a plane mirror forms
only a single image of an object. What
happens if two plane mirrors are used
in combination? Let us see.
Do We See all Objects due to Reflected Light?
Nearly everything you see around is seen due to reflected light. Moon, for example,
receives light from the Sun and reflects it. That’s how we see the moon. The objects
which shine in the light of other objects are called illuminated objects. Can you
name some other such objects?
There are other objects, which give their own light, such as the Sun, fire, flame
of a candle and an electric lamp. Their light falls on our eyes. That is how we see
them. The objects which emit their own light are known as luminous objects.
Fig. 13.9 : Mirror at the hair dresser shop
I have a question. Can the
reflected rays be further reflected
if incident on another mirror?
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Activity 13.5
Take two plane mirrors. Set them
at right angles to each other with
their edges touching (Fig. 13.10). To
hinge them you can use adhesive
tape. Place a coin in between the
mirrors. How many images of the
coin do you see (Fig. 13.10)?
Now hinge the mirrors using the
adhesive tape at different angles, say
45°, 60°, 120°, 180° etc. Place some
object (say a candle) in between
them. Note down the number of
images of the object in each case.
Finally, set the two mirrors
parallel to each other. Find out
how many images of a candle
placed between them are formed
(Fig. 13.11).
Fig. 13.10 : Images in plane mirror at right
angle to each other
Fig. 13.11 : Image in plane mirror parallel
to each other
mirrors
(a)
(b)
(c)
Can you now explain how you can
see the back of your head at the hair
dresser’s shop?
This idea of number of images formed
by mirrors placed at an angle to one
another is used in a kaleidoscope to
make numerous beautiful patterns. You
can also make a kaleidoscope yourself.
Kaleidoscope
Activity 13.6
To make a kaleidoscope, get three
rectangular mirror strips each about
15 cm long and 4 cm wide. Join
them together to form a prism as
shown in Fig. 13.12(a). Fix this
arrangement of mirrors in a circular
cardboard tube or tube of a thick
chart paper. Make sure that the tube
is slightly longer than the mirror
strips. Close one end of the tube by
a cardboard disc having a hole in
the centre, through which you can
see [Fig. 13.12(b)]. To make the disc
durable, paste a piece of transparent
plastic sheet under the cardboard
Fig. 13.12 : Making a kaleidoscope
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disc. At the other end, touching the
mirrors, fix a circular plane glass
plate [Fig. 13.12(c)]. Place on this
glass plate several small pieces of
coloured glass (broken pieces of
coloured bangles). Close this end of
the tube by a ground glass plate.
Allow enough space for the colour
pieces to move around.
Your kaleidoscope is ready. When
you peep through the hole, you will be
able to see a variety of patterns in the
tube. An interesting feature of a
kaleidoscope is that you will never see
the same pattern again. Designers of
wallpapers and fabrics and artists often
use kaleidoscopes to get ideas for new
patterns. To make your toy attractive,
you can wrap the kaleidoscope in a
colour
ed paper.
13.6 Sunlight — White or
Coloured
In Class VII, you learnt that the sunlight
is referr
ed to as white light. You also
learnt that it consists of seven colours.
Here is another activity (Activity 13.7)
showing that sunlight consists of several
colours.
13.7 What is inside Our Eyes?
We see things only when light coming
from them enters our eyes. Eye is one
of our most important sense organs. It
is, therefore, important to understand
its structure and working.
The eye has a roughly spherical
shape. The outer coat of the eye is
white. It is tough so that it can protect
the interior of the eye from accidents.
Its transparent front part is called
Activity 13.7
Fig. 13.13 : Dispersion of light
Get a plane mirror of a suitable size.
Place it in a bowl (katori) as shown
in Fig. 13.13. Fill the bowl with
water. Put this arrangement near a
window in such a way that direct
sunlight falls on the mirror. Adjust
the position of the
bowl so that the
reflected light from
the mirror falls on
a wall. If the wall is
not white, fix a sheet
of white paper on it.
Reflected light will
be seen to have
many colours. How
can you explain
this? The mirror
and water form a
prism. As you learnt in Class VII,
this breaks up the light into its
colours, Splitting of light into its
colours is known as dispersion of
light. Rainbow is a natural
phenomenon showing dispersion.
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Fig. 13.15 : Demonstration of blind spot
Caution : For this activity, never use
a laser torch.
Activity 13.8
Look into your friend’s eye. Observe
the size of the pupil. Throw light on
her eye with a torch. Observe the
pupil now. Switch off the torch, and
observe her pupil once again. Do
you notice any change in the size
of the pupil? In which case was the
pupil larger? Why do you think it
was so?
In which case do you need to
allow more light in the eye, when
the light is dim or bright?
Behind the pupil of the eye is a lens
which is thicker in the centre. What
kind of lens is thicker at the centre?
Recall what you learnt about lenses in
cornea (Fig. 13.14). Behind the cornea,
we find a dark muscular structure
called iris. In the iris, there is a small
opening called the pupil. The size of
the pupil is controlled by the iris. The
iris is that part of eye which gives it its
distinctive colour. When we say that a
person has green eyes, we refer actually
to the colour of the iris. The iris controls
the amount of light entering into the
eye. Let us see how.
Iris
Lens
Ciliary
muscle
Cornea
Retina
Optic
Nerve
Fig. 13.14 : Human eye
Class VII. The lens focuses light on the
back of the eye, on a layer called retina
(Fig. 13.14). The retina contains several
nerve cells. Sensations felt by the nerve
cells are then transmitted to the brain
through the optic nerve. There are two
kinds of cells–
(i) cones, which are sensitive to bright
light and
(ii) rods, which are sensitive to dim light.
Cones sense colour. At the junction
of the optic nerve and the retina, there
are no sensory cells, so no vision is
possible at that spot. This is called the
blind spot. Its existence can be
demonstrated as follows:
Activity 13.9
Make a round mark and a cross on
a sheet of paper with the spot to the
right of the cross (Fig. 13.15). The
distance between two marks may be
6-8 cm. Hold the sheet of paper at
an arm’s length from the eye. Close
your left eye. Look continuously at
the cross. Move the sheet slowly
towards you, keeping your eye on
the cross. What do you find? Does
the round mark disappear at some
point? Now close your right eye.
Look at the round mark now and
repeat the activity. Does the cross
disappear? The disappearance of the
cross or the round mark shows that
there is a point on the retina which
cannot send messages to the brain
when light falls on it.
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Nature has provided eyes with
eyelids to prevent any object from
entering the eye. Eyelids also shut out
light when not required.
Eye is such a wonderful instrument
that it (normal) can clearly
see distant
objects as well as objects nearby. The
minimum distance at which the eye can
see objects distinctly varies with age. The
most comfortable distance at which one
can read with a normal eye is about
25 cm.
Some persons can see objects close
to them clearly but cannot see distant
objects so clearly. On the other hand,
some persons cannot see objects nearby
clearly but they can see distant objects
quite well. With suitable corrective
lenses, these defects of the eye can
be corrected.
Sometimes, particularly in old age,
eyesight becomes foggy. It is due to the
eye lens becoming cloudy. When it
happens, persons are said to have
cataract. There is a loss of vision,
sometimes extremely severe. It is
possible to treat this defect. The opaque
lens is removed and a new artificial
lens is inserted. Modern technology
has made this procedure simpler
and safer.
13.8 Care of the Eyes
It is necessary that you take proper care
of your eyes. If there is any problem
you should go to an eye specialist. Have
a regular checkup—
l If advised, use suitable spectacles.
l Too little or too much light is bad
for eyes. Insufficient light causes
eyestrain and headaches. Too much
light, like that of the Sun, a powerful
The movies that we see are actually
a number of separate pictures in
proper sequence. They are made to
move across the eye usually at the rate
of 24 pictures per second (faster
than 16 per second). So, we see a
moving picture.
Front side of
cardboard
Reverse side
of cardboard
The impression of an image does not
vanish immediately from the retina. It
persists there for about 1/16th of a
second. So, if still images of a moving
object are flashed on the eye at a rate
faster than 16 per second, then the eye
perceives this object as moving.
Activity 13.10
Get a square piece of cardboard of
size 6-8 cm. Make two holes as
shown in Fig. 13.16. Thread a
string through the two holes. Draw/
paste a cage on one side of the
cardboard and a bird on the other
side. Twist the string and make the
card twirl rapidly. Do you see the
bird in the cage?
Fig. 13.16 : Bird in cage
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lamp or a laser torch can injure the
retina.
l Do not look at the Sun or a powerful
light directly.
l Never rub your eyes. If particles of
dust go into your eyes, wash your
eyes with clean water. If there is no
improvement go to a doctor.
l Always read at the normal distance
for vision. Do not read by bringing
the book too close to your eyes or
keeping it too far.
You learnt about balanced diet in
Class VI. If food is deficient in some
components, eyes may also suffer. Lack
of vitamin A in foodstuff is responsible
for many eye troubles. Most common
amongst them is night blindness.
One should, therefore, include in the
diet components which have vitamin A.
Raw carrots, broccoli and green
Did you know?
Animals have eyes shaped in different ways. Eyes of a crab are quite small but
they enable the crab to look all around. So, the crab can sense even if the enemy
approaches from behind. Butterflies have large eyes that seem to be made up
of thousands of little eyes
(Fig. 13.17). They can see not only
in the front and the sides but the
back as well.
A night bird (owl) can see very
well in the night but not during
the day. On the other hand, day
light birds (kite, eagle) can see
well during the day but not in the
night. The owl has a large cornea
and a large pupil to allow more
light in its eye. Also, it has on its
retina a large number of rods and
only a few cones. The day birds
on the other hand, have more
cones and fewer rods.
Fig. 13.17 : Eyes of a butterfly
Eyes
vegetables (such as spinach) and cod
liver oil are rich in vitamin A. Eggs,
milk, curd, cheese, butter and fruits
such as papaya and mango are also rich
in vitamin A.
13.9 Visually Impaired
Persons Can Read and
Write
Some persons, including children, can
be visually impaired. They have very
limited vision to see things. Some
persons cannot see at all since birth.
Some persons may lose their eyesight
because of a disease or an injury. Such
persons try to identify things by
touching and listening to voices more
carefully. They develop their other
senses more sharply. However,
additional resources can enable them
to develop their capabilities further.
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13.10 What is the Braille
System?
The most popular resource for visually
challenged persons is Braille.
Louis Braille
Louis Braille, himself a visually
challenged person, developed a
system for visually challenged persons
and published it in 1821.
Non-optical and optical aids for visually impaired
Non-optical aids include visual aids, tactual aids (using the sense of touch), auditory
aids (using the sense of hearing) and electronic aids. Visual aids, can magnify
words, can provide suitable intensity of light and material at proper distances.
Tactual aids, including Braille writer slate and stylus, help the visually challenged
persons in taking notes, reading and writing. Auditory aids include cassettes, tape
recorders, talking books and other such devices. Electronic aids, such as talking
calculators and computers, are also available for performing many computational
tasks. Closed circuit television, also an electronic aid, enlarges printed material
with suitable contrast and illumination. Nowadays, use of audio CDs and voice boxes
with computers are also very helpful for listening to and writing the desired text.
Optical aids include bifocal lenses, contact lenses, tinted lenses, magnifiers
and telescopic aids. While the lens combinations are used to rectify visual
limitations, telescopic aids are available to view chalkboard and class
demonstrations.
The present system was adopted in
1932. There is Braille code for common
languages, mathematics and scientific
notation. Many Indian languages can
be read using the Braille system.
Braille system has 63 dot patterns or
characters. Each character
represents a letter, a combination of
letters, a common word or a
grammatical sign. Dots are arranged
in cells of two vertical rows of three
dots each.
Patterns of dots to represent some
English letters and some common
words are shown below.
These patterns when embossed on
Braille sheets help visually
challenged persons to recognise words
by touching. To make them easier to
touch, the dots are raised slightly.
Fig. 13.18 : Example of dot patterns used
in Braille System
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Some visually impaired Indians have great achievements to their
credit. Diwakar, a child prodigy has given amazing performances
as a singer.
Ravindra Jain, born completely visually impaired, obtained
his Sangeet Prabhakar degree from Allahabad. He had shown his
excellence as a lyricist, singer and music composer.
Lal Advani, himself visually impaired, established an
Association for special education and rehabilitation of disabled
in India. Besides this, he represented India on Braille problems
in UNESCO.
Helen A. Keller, an American author and lecturer, is perhaps the most well-
known and inspiring visually challenged person. She lost her sight when she was
only 18 months old. But because of her resolve and courage she could complete
her graduation from a university. She wrote a number of books including The
Story of my Life (1903).
Helen A. Keller
Visually impaired people learn the
Braille system by beginning with
letters, then special characters and
letter combinations. Methods depend
upon recognition by touching. Each
character has to be memorised. Braille
texts can be produced by hand or by
machine. Typewriter-like devices and
printing machines have now been
developed.
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KEYWORDSKEYWORDS
KEYWORDSKEYWORDS
KEYWORDS
ANGLE OF
INCIDENCE
ANGLE OF
REFLECTION
BLIND SPOT
BRAILLE
CONES
CORNEA
DIFFUSED OR
IRREGULAR
REFLECTION
INCIDENT RAYS
IRIS
KALEIDOSCOPE
LATERAL INVERSION
LAWS OF
REFLECTION
PUPIL
REFLECTED RAYS
REFLECTION
REGULAR
REFLECTION
RETINA
RODS
WHAT YOU HAVE LEARNT WHAT YOU HAVE LEARNT
WHAT YOU HAVE LEARNT WHAT YOU HAVE LEARNT
WHAT YOU HAVE LEARNT
Ü Light is reflected from all surfaces.
Ü Regular reflection takes place when light is
incident on smooth, polished and regular
surfaces.
Ü Diffused or irregular reflection takes place from
rough surfaces.
Ü Two laws of reflection are
(i) The angle of incidence is equal to the angle
of reflection.
(ii) Incident ray, reflected ray and the normal
drawn at the point of incidence to the
reflecting surface, lie in the same plane.
Ü Image formed in a plane mirror undergoes
lateral inversion.
Ü Two mirrors inclined to each other give multiple
images.
Ü Beautiful patterns are formed in a
kaleidoscope because of multiple reflections.
Ü Sunlight, called white light, consists of seven
colours.
Ü Splitting of light into its constituent colours is
known as dispersion.
Ü Parts of the eye are cornea, iris, pupil, lens,
retina and optic nerve.
Ü A normal eye can see nearby and distant
objects clearly.
Ü Visually impaired persons can read and write
using the Braille system.
Ü Visually impaired persons develop their other
senses more sharply to improve their interac-
tion with their environment.
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Exercises
1. Suppose you are in a dark room. Can you see objects in the room? Can
you see objects outside the room. Explain.
2. Differentiate between regular and diffused reflection. Does diffused
reflection mean the failure of the laws of reflection?
3. Mention against each of the following whether regular or diffused reflection
will take place when a beam of light strikes. Justify your answer in each
case.
(a) Polished wooden table (b) Chalk powder
(c) Cardboard surface (d) Marble floor with water
spread over it
(e) Mirror (f) Piece of paper
4. State the laws of reflection.
5. Describe an activity to show that the incident ray, the reflected ray and
the normal at the point of incidence lie in the same plane.
6. Fill in the blanks in the following.
(a) A person 1 m in front of a plane mirror seems to be _______________ m
away from his image.
(b) If you touch your ____________ ear with right hand in front of a plane
mirror it will be seen in the mirror that your right ear is touched with
____________.
(c) The size of the pupil becomes ____________ when you see in dim light.
(d) Night birds have ____________ cones than rods in their eyes.
Choose the correct option in Questions 7 – 8
7. Angle of incidence is equal to the angle of reflection.
(a) Always (b) Sometimes
(c) Under special conditions (d) Never
8. Image formed by a plane mirror is
(a) virtual, behind the mirror and enlarged.
(b) virtual, behind the mirror and of the same size as the object.
(c) real at the surface of the mirror and enlarged.
(d) real, behind the mirror and of the same size as the object.
9. Describe the construction of a kaleidoscope.
10. Draw a labelled sketch of the human eye.
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11. Gurmit wanted to perform Activity 13.8 using a laser torch. Her teacher
advised her not to do so. Can you explain the basis of the teacher’s advise?
12. Explain how you can take care of your eyes.
13. What is the angle of incidence of a ray if the reflected ray is at an angle of
90° to the incident ray?
14. How many images of a candle will be formed if it is placed between two
parallel plane mirrors separated by 40 cm?
15. Two mirrors meet at right angles. A ray of light is incident on one at an
angle of 30° as shown in Fig. 13.19. Draw the reflected ray from the second
mirror.
Fig. 13.19
16. Boojho stands at A just on the side of a plane mirror as shown in
Fig. 13.20. Can he see himself in the mirror? Also can he see the image of
objects situated at P, Q and R?
Fig. 13.20
17. (a) Find out the position of the image of an object situated at A in the
plane mirror (Fig. 13.21).
(b) Can Paheli at B see this image?
(c) Can Boojho at C see this image?
(d) When Paheli moves from B to C, where does the image of A move?
Fig. 13.21
E X E R C I S E S
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SCIENCE180
Extended Learning — Activities and Project
1. Make your own mirror. Take a glass strip or glass slab. Clean it and
put it on a white sheet of paper. See yourself in the glass. Next put
the glass slab on a black sheet of paper. Again look into the glass.
In which case do you see yourself better and why?
2. Make friends with some visually impaired students. Enquire from
them how they read and write. Also find out how they are able to
recognise objects, hurdles and currency notes.
3. Meet an eye specialist. Get your eye sight checked and discuss how
to take care of your eyes.
4. Survey your neighbourhood. Find out how many children below
the age of 12 years use spectacles. Find out from their parents
what, in their view, could be the reason for the weak eyesight of
their children.
Did You Know?
Eyes can be donated by any person as an invaluable gift to visually
impaired persons suffering from corneal blindness, The person may be
(a) a male or female.
(b) of any age.
(c) of any social status.
(d) using spectacles.
(e) suffering from any normal disease but not AIDS, Hepatitis B or C,
rabies, leukemia, lymphoma, tetanus, cholera, encephalitis.
The eyes have to be donated within 4-6 hours after death at any
place, home or hospital.
A person who wants to donate the eyes may pledge eyes during his/her
lifetime to any registered eye bank. He/she should also inform his/her
relatives about this pledge so that they can take necessary action after
his/her death.
You can also donate a Braille kit.
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Notes
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Notes
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